Many photoresist strippers and residue removers have been proposed for use in microelectronics manufacturing. Many stages of microelectronic device construction involve a thin film of photoresist which is deposited on a substrate material and imaged to produce the circuit design. The resulting image is utilized to pattern the underlying material, which could be a dielectric or metal layer, using plasma etch gases or solvent-based chemical etching. Following this etching step, the resist mask must be removed from the protected area of the substrate so that the next process operation can take place. The photoresist may be removed directly by wet chemical strippers, or largely removed by ashing of the bulk material followed by residue removal. Finding a cleaning composition for the removal of bulk resists and ashed residues can be challenging. The etching process can modify bulk polymer, increasing cross-linking and making the resist more difficult to remove. Similar cross-linking can be faced when the ashing step is partial or incomplete, and ashed residues on feature sidewalls can prove difficult to remove. Additionally, the cleaning solution must provide adequate cleaning while protecting all exposed metals and dielectrics from corrosion or etching. This is of particular interest in areas of microelectronic development requiring compatibility with numerous materials simultaneously, each with unique compatibility requirements.
Many alkaline microelectronic stripping and cleaning compositions have been proposed for the removal of cross-linked and hardened photoresists and other residues, such as post etch residues, from such microelectronic substrates. However, one problem with such stripping and cleaning composition is the possibility of metal corrosion occurring as a result of the use of such cleaning compositions. Such corrosion results in whiskers, pitting, notching of metal lines, and selective loss of metal from alloys due at least in part to the reaction of the metals in the device substrates with the alkaline strippers employed. One such alkaline microelectronic stripping and cleaning composition is that disclosed in U.S. Pat. No. 5,308,745. While the stripping and cleaning compositions of that patent have been commercially employed to strip hardened and cross-linked photoresist from substrates, it has been discovered that attempts to clean microelectronic substrates having various exposed metal layers with the cleaning composition of this patent has resulted in significant metal corrosion or insufficient cleaning of the resists or residues.
There is, therefore, a need for microelectronic stripping and cleaning compositions that can effectively remove bulk residues resists and ashed residues and do so without any significant metal corrosion or substrate attack resulting from the stripping and cleaning composition. There is also a need for such compositions that provide corrosion protection for numerous materials present in microelectronics manufacture exposed to the cleaning chemistry in the same cleaning step.